Machine tool



Jan. 24, 1939- B. GRANBERG ET AL MACHINE TOOL Filed Feb. 29, 1936 llSheets-Sheet l gag y:

kn. 24, 1939. B, GRANBERG Er AL 2,144,735

MACHINE TOOL ll Sheets-Sheet 2 Filed Feb. 29, 1936 Jan. 24, 1939. a.GRANBERG ET AL MACHINE TOOL Filed Feb. 29, 1936 11 Sheets-Sheet 3 fa/f/fm Jan. 24, 1939. 3 GRANBERG ET AL 2,144,735

MACHINE TOOL Filed Feb. 29, 1936 ll Sheets-Sheet 4 Jan. 24, 1939. B.GRANBERG ET AL 2,144,735

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Ill/1111111177711 Jan. 24, 1939. B. GRANBERG ET AL MACHINE TOOL llSheets-Sheet 6 Filed Feb. 29, 1936 Jan. 24, 1939. GRANBERG ET AL2,144,735

MACHINE TQOL Filed Feb. 29, 1936 ll Sheets-Sheet 7 Jan. 24, 1939. B.GRANBERG ET AL MACHINE TOOL Filed Feb. 29, 1936 ll Sheets-Sheet 8 we /4/a4 B. GRANBERG ET AL Jan. 24, 1939.

MACHINE TOOL l1 Sheets-Sheet 9 Filed Feb. 29, 1936 N\% Mm M N k \MM. J6/ A I Ir m i l m \\w m H 0 I! m $6 \kh A mm h mm M l um 1 La v Jan. 24,1939. B. GRAN B ERG ETAL 2,144,735

' momma TOOL Filed Feb. 29, 1956 ll Sheets-Sheet 10 Jan- 2 1939- B.GRANBERG ET Al. 2,1

MACHINE TOOL l1 Sheets-Sheet 11 Filed Feb. 29, 1936 ?atenied den. 24%,l3

STATES ram MACHINE TOOL Bengt Granberg and John B. Sinderson, Rock--ford, Ill., assignors to Sundstrand Machine Tool 00., Rockford,'lll., acorporation ofIllinois Application February 29, 1936, Serial No. 66,463

55 Claims.

of and a rear carriage adjustable longitudinally.

thereof and carrying a tool slide, novel and improved drive means foractuating the front carriage at rapid approach, feed and rapid returnspeeds and for actuating the rear tool slide.

Yet another object is to provide in a lathe, having a front carriagereciprocable longitudinally thereof and a rear carriage adjustablelongitudinally thereof and carrying a tool slide, novel and improveddrive means for the front carriage and the rear tool slide which iscompletely and efiectively isolated by walls of metal from coolant andchips and is operable to actuate the rear tool slide over a Wide rangeof positions of the rear carriage longitudinally of the lathe and topermit such positioning of the rear carriage without disconnection oradjustment of the drive means for the rear tool slide.

A further object is to provide in a lathe having a carriage, a drive forthe-carriage including a planetary gearing, a first element of which isdriven by the spindle and a second element of which is driven by a rapidtraverse motor, a solenoid brake applied upon deenergization of therapid traverse motor to stop the second element, a detent device adaptedto engage a notched portion of the second element to hold the sameagainst rotation, and a governor controlling the detent devicepermitting engagement thereof only upon cessation of rotation of thesecond element.

Still a further object is to provide in a lathe of the characterdescribed a simplified and improved electrical control readily adjustedto obtain the cycle desired or to change from partial to full automaticcontrol, and prohibiting shift from feed to rapid approach to preventinjury to the work.

Yet a further object is to provide a lathe having a carriagereciprocable longitudinally thereof and hardened and ground steel wayson which the carriage reciprocates, resulting inlonger life of the latheand greater precision in the operation thereof.

taken in connection with the accompanying drawings, in which:

Fig. 1 is a front elevational view of a lathe embodying the features ofthe invention with a portion of the chip pan, the cover for the spindlechangegearing, and the cover for the drum switch control removed.

Fig. 2 is a top plan View of the lathe shown in Fig. 1.

Fig. 3 is a left end elevational view of the lathe shown in Fig. 1 witha portion of the cover housing the drive to the spindle broken away toreveal the solenoid brake for the spindle.

Fig. 4 is a diagrammatic view illustrating the driving connections forthe spindle, the front carriage and the rear cross slide.

Fig. 5 is a horizontal axial section of the spindle taken along line 55of Fig. 1.

Fig. 6 is a sectional view taken along lines 6-6 of Figs. 1 and 2 toshow the construction of the front carriage and cross slide, the rearcarriage and cross slide, and the drive for the rear cross slide.

Fig. 7 is a fragmentary rear elevational view of the rear cross slide.

Fig. 8 is a sectional view taken along lines 8-8 of Figs. 1 and 6.

Fig. 9 is 'a sectional view taken along line 9-9 of Fig. 3.

Fig. 10 is a detailed view of the overload release clutch in the driveto the carriages.

Fig. 11 is a diametrical section taken along line ll--l l of Fig. 12showing the rapid traverse brake and detent device slightly enlargedover and in a different position from that shown in Fig. 9.

Fig. 12 is a sectional view taken along line l2-I2 of Fig. 11.

Fig. 13 is a vertical diametrical section of: the

drum switch, control taken along line Iii-l6 of Fig. 13.

. Fig. 17 is, a transverse sectional view of the drum switch controltaken along line I'Il'| of Fig. 13.

Fig. 18 is a transverse sectional view of the drum switch control takenalong line l8--l8 of Fig. 13.

Fig. 19 is a transverse sectional view of the drum switch control takenalong line |9--|3 of Fig. 13 and looking in a direction opposite toFigs. 16 to 18.

Fig. 20 is a wiring diagram of the electrical connections for the motorsand the control means therefor.

While the invention is susceptible of various modifications andalternative constructions, it is here shown and will hereinafter bedescribed in a preferred embodiment, but it is not intended that theinvention is to be limited thereby to the specific constructiondisclosed, but it is intended to cover all modifications and alternativeconstructions falling within the spirit and scope of the invention asdefined by the appended claims.

General construction The lathe illustrated in the drawings andhereinafter described for purposes of disclosure comprises generally abase 25, a bed 26 and a headstock 21'at one end of the bed, all formedas an integral part of a single casting, well ribbed to provide strengthand rigidity. Also cast integrally with the base and the bed at thejuncture thereof is a coolant and chip trough 28 extending around threesides of the lathe. Supported on the trough 28 by means of brackets 29is a chip pan 30, a section of which at the rear of the lathe isremovable to facilitate removal of chips. A spindle 3| driven by anelectric motor 32 is rotatably mounted in the headstock 21, andadjustably mounted for movement longitudinally of the bed, opposite thespindle at the other end of the bed, is a tailstock 33. The tailstockhas a removable center 34 received in a quill 35 which is clamped orreleased by a lever 36 and when released is shifted axially by a'lever31. The tailstock is secured in adjusted position by bolts 38.

Reciprocable longitudinally of the bed 26 is a front carriage 39carrying a cross slide 40 for the support of a tool (not shown). Hereinthe carriage is driven in a forward direction at traverse and feedspeeds and in a return direction at traverse speed by suitable drivingmeans including a planetary gearing generally designated A (see Figs. 4and 9), and a power unit generally designated B (see Figs. 4,6 and 8). Afirst driving element of the planetary gearing is actuated from thespindle 3|, while a second driving element of the planetary gearing isactuated by a reversible electric motor 43. To drive the carriage atfeed speed the first element is driven by the spindle, while the secondelement is held against rotation by the motor 43 and more particularlyby a rapid traverse brake and detent device shown in Figs. 11 and 12. -Arapid traverse movement of the carriage in either direction is obtainedwith or without rotation of the first element through rotation of thesecond element in the proper direction by the reversible electric motor43. Adjustable longitudinally of the bed 26 is a rear carriage 45supporting a cross slide 46 which is driven from the power unit Bintimed relation to the movement of the front carriage.

The lathe is controlled electrically and the parts driven throughvarious cycles of operation without the aid of clutches by starting andstopping of the motors. Such starting and stopping of the motors ispartially under the control of a push button station 48 and partiallyunder the control of a drum switch and control generally designated 49.This drum switch control may be adjusted so that the lathe issemi-automatic with each cycle of operation initiated by the operator ofthe lathe through a lever 56, or so that the operation is continuous andwholly automatic.

Spindle drive The spindle 3| is journaled at its forward end (Fig. 5) intwo tapered roller bearings 52 and at its rear end in a single ballbearing 53, and'at that end projects from the headstock. Keyed to thespindle intermediate the bearings is a large beveled gear 54 whichmeshes with a bevel pinion 55 keyed to one end of a stub shaft 56projecting at the other end through the front face of the headstock 21.Secured to the projecting end of the stub shaft 66 is a gear 41 meshingwith a gear 58 (see Fig. 1) fast on the end of a shaft 58 extendingtransversely of the headstock and at its other end carrying a pulley 60.The drive for the spindle (Fig. 3) is completed by V-belts 6| runningover the pulley 60 and a drive pulley 62 fast on the shaft of the motor32. Gears 51 and 53 constitute change gears for varying the speed of thespindle 3| and are encased in a cover 63 readily removable to facilitatechanging of the gears. The pulleys 66 and 62 and the V-belts arelikewise encased in a removable housing 64 in order that the danger ofinjury to an operator of the machine may be reduced. In order that theten: sion of the V-belts 6| may be adjusted, the motor 32 is pivotallymounted in well known manner upon a shaft 65 and is retained in thedesired position by adjusting screw 65' (see Fig. 2). The motor 32preferably is protected by a shield 32.

Herein the spindle 3| is rotated only while the front carriage 39 ismoving in a forward direction and isstopped during the return movementof the carriage. In order that the spindle may be quickly brought torest after reversal of the carriage, there is secured to the shaft 59 abrake drum 66. Encircling the brake drum 66 is a brake band'61 (see Fig.3) which is applied by a spring 68 and which is released by a solenoid69. This solenoid, as will become apparent later, is energized torelease the brake when the motor 32 is energized and is deenergized topermit the spring 68 to apply the brake when the motor 32 isdeenergized.

Front carriage, cross slide and drive As previously stated, there isreciprocable longitudinally of the bed 26 a front carriage 39. To

prolong the life of the machine and to obtain greater precision inoperation, the front carriage 39 slides on a hardened and ground steelway 1| secured to the bed 26. The carriage is adjusted and wearcompensated for by means of a taper gib 12 and a taper gib 13 (Fig. 6)interposed between vertical and inclined surfaces respectively of thecarriage and the way 1|.

Supported on the carriage is a cross slide 40 (Fig. 6) adapted tosupport a tool (not shown). The slide is formed with a longitudinal bore15 in which is movable a cylindrical member 16. At its inner end, thecylindrical member 16 carries a pin 11 projecting downwardly through aslot 18 formed in the slide and into a groove 19 in the upper face ofthe carriage 39. At the end projecting into the groove 19, the pin 11carries a roller 60 adapted to engage a cam bar 8| providing automaticfeed-in of the tool. Also disposed in the groove 19 are bars 62 and 83providing for automatic tool relief at the end of the cut. The'cam bar8| is secured to the bed 26 of the lathe by a bracket 34 (Fig. 1) andthe bars 82 and 83 are shifted relative to one another at the beginningand the end of the cut as more particularly described and claimed in thepatent to Timothy B. Buell No. 2,082,933, issued May 28, 1935. Theroller 88 (Fig. 6) is held in engagement with the cam bar III by acompression spring 85 held in place by a rod 86 and at one end abuttingthe carriage 39 and at the other end abutting a plate 8'7 secured to theend of the slide 48. Rotatable in the plate 8?, but held against axialmovement relative thereto, is a micrometer screw 88 threaded into thecylindrical member III. The projecting end of the micrometer screw 88 isformed to receive a tool and carries a dial 89 to facilitate accurateadjustment of the slide transversely of the carriage by rotation of thescrew 88. Mounted on the carriage 39 and disposed on each side of theslide 48 are plates 98 and M (Fig. 2) providing a convenient support fortools or the like.

The carriage 39 is driven at traverse and feed speeds in a forwarddirection and at traverse speed in a return direction by means whichherein includes the differential or planetary gearing generallydesignated A and the power unit generally designated B. Herein theplanetary gearing (Fig. 9) comprises a carrier 95 having teeth 96 formedon the periphery thereof, a sun gear- 91 and a sun gear 98 having aslightly larger number of teeth than the gear 91. Meshing with the sungear 97 aretwo planet gears 99 each keyed to a shortshaft I88 journaledin the carrier 95. Meshing with the sun gear 98 are two planet gears I8Ihaving a slightly smaller number of teeth than the planet gears 99 andeach keyed to one of the shafts I88.

One driving element of the planet gearing, herein the carrier 95, isdriven, to impart a feed movement to the carriage 39, by the spindlemotor 32 through the spindle 3i and suitable gearing generallydesignated I83 which, with the planetary gearing, is assembled andhoused in a casing I84 secured as a unit to the end of the bed of thelathe. The gearing I83 comprises a sprocket wheel I85 keyed to the endof the spindle 3I projecting from the headstock 21 from which a chainI86 drives a sprocket I8I rotatable on a stub shaft I88. Formedintegrally with the sprocket I87 is a gear I89 meshing with a gear II8rotatable on a shaft II I. The gear II8 has teeth II2 on one facethereof so as to form one element of a clutch, the shiftable element H3of which is formed with complementary teeth and is splined to one end ofa shaft H4. The other end of the shaft H4 also is splined and projectsfrom the casing I84 to receive a gear II5 meshing withja gear II6splined to a shaft III which also projects from the casing I84.-

Keyed to the shaft I II is a gear I I8 meshing with a gear II9 in turnmeshing with the teeth 96 of the planetary carrier 95 to complete thedrive to the carrier. Gears H5 and H6 constitute change gears and areretained on the shafts H4 and I II by a removable cover I28. The coveris formed with an aperture I2I opposite the shaft 4 for the insertioninto engagement with the shaft N4 of a tool whereby the carriage may beactuated manually when the clutch H3 is disengaged, The arms of a yokeI22 engage a groove I23 formed in the shiftable clutch element II 3' andthe yoke is fixed by a set screw I24 to a shaft I25 projecting outwardlyof the casing I84 and rocked by a lever I26 for manual-engagement ordisengagement of the clutch II3 (see Fig. 1).

A second driving element, herein the sun gear 971 (Fig. 9), is rotatedat a high speed and in either direction by the reversible electric motor43 to impart a rapid traverse movement to the carriage 39. To that endthe sun gear 91 is fast on a'shaft I38 which is journaled at I3I in acasting I84 bolted to the casing I84 over an opening therein. At one endthe shaft I38 projects through the planetary gear carrier 95 and into arecess in the sun gear 98. The other end of the shaft I38 projects fromthe casting I84 and is splined to receive a member I32 constituting apulley I33 anda brake drum I34. The member I32 is retained on thesplined end of the shaft I38 by a nut I35. Running in grooves I36 in thepulley I33 are V-belts I31 running in similar grooves formed in a pulleyI36 secured to the shaft of the reversible motor '43 (see Fig. 3).

A solenoid brake and a detent device are provided for holding the sungear 91 against rotation when it is desired to impart a feed movement tothe carriage 39. The brake comprises shoes I48 and MI (see Figs. 11 and12) pivoted at their lower ends by pins I42 on a portion of the castingI84. The shoes I48 and MI are applied to the brake drum I34 by springpressure and are released by means of a solenoid I43. To that end, theupper end of the shoe I48 is forked to form arms I44 and the shoe I4Ilikewise is forked to form arms I45. Pivoted between the arms I44 is ablock I46 through which projects loosely a threaded rod I41 carrying atits end an adjusting nut I48. Interposed between the nut I48 and theblock I46 is a compression spring I49 which provides the force forapplying the brake. The other end of the rod I41 is flattened at HIV andprojects beyond the arms I45 of shoe MI and is disposed between angularlinks I58. The flattened end I41 of the rod I4?! is secured to the linksI58 by a pin I58. substantially at the bend in the links which isoutwardly of the arms I45, while the links I58 in turn are pivoted attheir inner ends to the arms I45 and at their outer ends to the core I5Iof the solenoid I43 through a swivel plate I52. Disposed underneaththe.links I58 and the flattened end I4'I of the rod I4! is a plate I53against which abuts one end of a compression spring I54, the other endof which is received in a socket I55 formed in the brake shoe MI andserves to lift the core I5I when the solenoid is deenergized. In orderthat downward movement of the core I5I of the solenoid, as viewed inFig. 12, may serve to release the brake, the rod I4! carries nuts I56which engage the block I46 to swing the shoes I48 and I4! outwardlyagainst the action of the spring I49.

, The braking torque required to bring sun gear. 91 to rest in thechange from traverse to feed' is not excessive and may be supplied by afriction brake of moderate size. However, when out of the tool duringfeed movement commences, the torque tending to rotate gear 91 isextremely high. In 'order that with a friction brake of moderate sizethe sun gear 91 may be held against rotation under that condition, themechanical detent device is provided for aiding and supplementing thebrake after the gear has been brought to rest. To that end there ismounted on the member I 32 an annular ring I68 held against rotationrelative to the member by a pin I 6I. The periphery of the annular ringI68.is formed with notches I62 with which is engageable a pawl I63pivoted at I64 on a lug of the casting I84. The pawl is urged to engagedposition, shown in Figs. 9 and 12, by a tension spring I65 at one endengaging a pin extension I66 of the pawl and at the other end adjustablyanchored by a screw I01. The pawl I63 is pivoted at its disengagedposition, shown in Fig. 11, and in dotted outline in Fig. 12, by anextension of a pin I68 projecting over the rear end of pawl I63i Pin I68extends through links I50 and plate I52 pivotally to connect the sameand is thus moved downwardly when solenoid I43 is energized. As willbecome apparent with the description of the electric circuits of thelathe, the solenoid I43 is connected in parallel with the motor 43 so asto be energized when the motor is energized and thus serves to releasebrake snoes I40 and MI and also withdraw pawl I63 when the motor 43 isenergized.

In order that pawl I63 may not engage a notch I62 before the member I32has stopped rotating, means responsive to rotation of the member I32 isprovided herein for maintaining pawl I63 in disengaged position afterdeenergization of the solenoid I43 and prior to cessation of rotation ofthe member I32. This means comprises a latch I10 pivoted near its lowerend on a pin HI and at its upper end disposed below a pin I12 projectingfrom the pawl I63. The pin I12 has a notch I13 and the latch I10likewise has a notch I14 so that in one position of the latch I10 thefinger I12 rests on the end of the latch, as shown in Fig. 11, therebyholding the pawl out of engagement with the notches I62. In anotherposition, the end of the latch I10 is received in the notch I13, asshown in Fig. 9, permitting finger I12 to drop and the pawl I63 toengage a notch I62. The latch is urged to the position shown in Fig. 9,that is with its end in notch I13, by a compression spring I16 abuttingan adjusting plug I11 carried by the latch I10 at its lower end.

During rotation of the member I32, the latch I10 is held inpawl-disengaged position against the opposition of the spring I16 by acentrifugal governor generally designated I carried by the member I32.The governor comprises a body I8I secured to the member I32 anddiametrically oppositely disposed weights I82 pivoted to the body I8I.Slidable in a bore I83 in the body is a plunger I84 having a groove I85into which fingers I86 of the centrifugal weights I82 project to movethe plunger outwardly of the bore when the weights are swung radiallyoutwardly by rotation of the member I32. The plunger I84 engages a ballI81 carried by the latch I10 intermediate its ends. The tension ofspring I16 is so adjusted that it is overcome by the weights I82 so longas there is any rotation of the member I32. In that manner the upper endof the latch I10 is held outwardly by the centrifugal governor so longas there is any rotation of the member I32, thereby assuring that thepawl I63 does not engage a notch I62 before cessation of rotation, whichwould cause great shock and perhaps injure the lathe. The traverse motor43, the belts I31 leading to the member I32 and the solenoid brake,detent device and control mechanism therefor are all encased in aremovable cover I88 secured to the casing I04.

The driven element of the planetary gearing, herein the sun gear 98, isformed integral with a shaft I90 terminating in a reduced threaded endI9I projecting into the bed 26 of the lathe. Keyed to the shaft I90intermediate its ends (see Fig. 10) is oneelement I92 of an overloadrelease, the other element I93 of which is formed on the end of a sleeveI94 loose on the shaft I90. The elements I92 and I93 are normally,retained in enspring I 95, at one end abutting the sleeve I84 and at theother end abutting a collar I96 which is mounted on ball bearings I91and is adjustable axially of the shaft by lock nuts I98 to vary the loadat which the release disengages. Formed on the sleeve I94 is a gear 200which meshes with a gear 20I keyed to a shaft 202 parallel with theshaft I90 and also projecting into the bed 26 of the lathe. Theoverloadrelease and the gears 200 and 20I are enclosed in a small housing 203bolted to the casing I04 and projecting through an aperture 204 formedin the end wall 205 of the bed 26 for that purpose.

7 As previously stated, the drive for the front carriage 39 includes apower unit B which comprises (see Figs. 6 and 8) a short shaft 201extending transversely of the lathe. The shaft 201 is journaled in thewalls of a box-like housing 206 adapted to be inserted into the bed ofthe lathe through an opening 209 in the front wall 2I0. The housing isformed in part by a plate 2 adapted to be removably secured over theopening 209 by bolts 2". One end of the shaft 201 projects outwardlythrough the plate 2 and is formed with a pinion 2I2 meshing with a rackbar 2 I3 secured by bolts 2 I3 to the bottom of the front carriage 39.The other end of the shaft 201 projects through and is journaled in awall 208' of the housing 208 and this wall is formed with a hub portion2I4. Keyed to the shaft 201 is a worm wheel 220 and meshing therewith isa worm 22I fast on a shaft 222 projecting outwardly of the housing 208.The end of the shaft 222 projecting outwardly of the housing 208 carriesone element of a universal joint 223, the other element of which issecured to a shaft 224 having a splined end 225. Completing the drive isa sleeve 226 slidable over the splined end 225 of the shaft 224 andsecured to one element of a universal joint 221 the other element ofwhich is carried by the shaft 202. Access to the universal joint 221 isprovided through an opening 228 in the bed 26 concealed by'a removablecover 229, and access to the universal joint 223 is had through anopening 230 in the 'plate 2 overlapping the opening 209 and concealed bya removable cover 23I. The power unit runs in a bath of oil contained inthe housing 208 and preferably a sight oil gage 232 is provided in theplate 2 to indicate the level of the oil in the housing.

It will be apparent from a consideration of Figs. 6, 8 and 9 that theribbing in the casting forming the bed is employed not only to providestrength, but to shield the drive for the front carriage from coolantand chips. In the present construction, the drive for the front carriageis completely isolated from coolant and chips by solid walls of metalincluding and wall 205, front wall 2I0 and rear wall 231 of the bed, awall 238 separating the headstock from the bed, and a reinforcing rib239 (see Figs. 6 and 8). The rib 239 opposite the power unit B has aportion 239 inclined downwardly and inwardly from the upper front edgeof the bed to the housing 208, a portion 239" extending around thehousing and outwardly to the front wall 2I0, and a vertical portion 239"extending laterally to the rear wall 231 and from the wall 238 to thebottom of the bed. This rib is formed with an aperture 24I through whichprojects one end of the shaft 201 and in which is piloted the hubportion 2 of the housing 208 in which the shaft 201 is journaled. Theportion of the opening 209 not closed by the plate 2 is gagement withone another by a compressioneflec y c o y t c se 39.

asaa 785 on which the ways 250 are formed. As best seen Rear carriage,cross slide and" drive Manually slidable longitudinally of the bed onways (Fig. 6) 25d and 2% is the rear carriage 95 secured in adjustedposition by bolts 252 and having a horizontal portion 95' and adepending vertical portion 95". Slidable transversely of the carriage 55(Fig. 7) on a generally T-shaped guideway 253 is the cross slide 46. Atthe ends of its horizontal portion the T-shaped guideway has inclinedguide surfaces 254. The cross slide 36 has complementary inclinedsurfaces 255 and in addition has rectangular portions 256 with guidesurfaces thereon projecting beneath the ends of the horizontal portionof the T-shaped guideway. Interposed between one of the inclined guidesurfaces 254 on the guideway and a complementary surface 255 on theslide is an adjustable tapered gib 251 for initially adjusting the crossslide and for compensatingfor wear of the guideway. With the guidesurfaces formed and the gib located as here shown, a single gib servesto maintain all complementary sliding surfaces in close contact.

Secured as by bolts 260 to the rear end of the slide 46 is a plate 26lin which is journaled a micrometer screw 262 threaded into a. bore 263in a block 264. This block is releasably secured beneath the slide 46 bymeans of a bolt 265 threaded into a T-nut 266 in a transverse T-slot 261in the upper surface of the block. At its outer end, the screw 262carries a Vernier dial 268 and is formed for the reception of a tool forrotating the screw to adjust the slide 46 relative to the block 264.

The cross slide 46 is reciprocated transversely of the lathe in timedrelation to the movement of the front carriage 39. To that end there issecured beneath the block 264 a roller 210 projecting into a cam groove2' formed in the periphery of a drum cam 212. The cam is keyed to ashaft 213 journaled in the rear carriage transversely thereof and faston the outer end of the shaft is a gear 214 meshing with a gear 215 faston the outer end of a short parallel shaft 216. The gears 214 and 215constitute change gears and are removably retained on the ends of shafts213 and 216 by a cover 211 removably secured to the rear carriage. Theinner end of the shaft 216 has secured thereto one element of auniversal joint 219, the other element of which is secured to a sleeve280. Completing the drive from the power unit B to the rear cross slideis a shaft 28l which at one end is splined to be received within thesleeve 280 and at the other end carries one element of a universal joint282, the other element of which is carried by the shaft 201 of the powerunit.

It will be apparent that by the provision of two universal joints in thedrive connection from the power unit to the rear cross slide, the rearcarriage may be adjusted to any position longitudinally of the bedWithout change or disconnection of the drive to the rear cross slide.-

to the rear cross slide is also completely isolated from coolant andchips. As best seen in Figs. 6 and 8, the shaft 28l is disposed in aconical housing formed by a rib 283 extending from the rib 239 to therear wall of the bed. The rib merges at itstop with the portion of thebed in Fig. 8, the housing formed by the rib 283 diverges from the frontto the rear of the lathe enabling the rear carriage to be adjusted toeither side of the position shown, as indicated by the dotted outlinesof the shaft 28L The depending portion 45" of the rear carriageeffectively closes the opening in the rear wall through which the shaft28! projects.

Coolant is supplied to the tools by a pump 285 (see Figs. 2 and 3)driven by an individual electric motor 286. The pump is of thecentrifugal type and is connected directly to the base 25 of the lathewhich is recessed and has a drain opening 281 to collect the coolant andreturn the same to the pump. In this manner the only piping required isthat leading from the pump to the tool.

Control Herein the front carriage 39 is operated through a cycle ofrapid approach, feed and rapid return and each such cycle may beinltiated by the operator, or the cycles may be automatically repeated.A rapid approach movement of the front carriage is obtained by actuationof both the spindle motor 32- and the rapid traverse motor 43, while afeed movement is obtainedby actuation of the spindle motor only, andrapid return is obtained by actuation of the rapid traverse motor onlyin a reverse direction. The rear cross slide, as previously stated, isactuated in timed relation to the reciprocation of the front carriageand the character of the movement imparted thereto is determined by thechange gears 214 and 215 and by the shape of the cam groove 21LElectrical control means is provided for governing the operation of thelathe and'comprises a drum switch (Fig. 13) generally designated 290,partially under the control of the operator of the lathe through thelever 50 and partially under the control of means 29| driven in timedrelation to the movement ofv the front carriage, and a push buttonstation 48 for conditioning the electrical circuits. The push buttonstation 48 and the drum switch 290 are best shown in Figs. 1 and 13 to19, while Fig. 20 is a diagrammatic showing of the control means, towhich figures reference will be made in the following description of thecontrol means.

The drum switch 290 directly controls the current to the rapid traversemotor 43 and governs the control current for the stopping and startingof the motor 32. To that end the switch comprises three metallic contactbrackets 292, 293 and 294 mounted in axially spaced relation on a squareshaft 295. The shaft is encased in insulation 296 and the brackets aremounted on the shaft with one corner thereof received in a V-shapedportion of each bracket and retained in that position by a. spring 291tensioned by a screw 298. Bracket 292 is formed with diametricallyoppositely disposed single segmental contact shoes 299 and 300, anddouble segmental contact shoes 30l and 30l' disposed between thecontacts 299 and 300. Bracket 293 likewise is formed with diametricallyoppositely disposed segmental contact shoes 302 and 303 and with doublesegmental contact shoes 304 and 304' disposed between shoes 302 and 303.Contact shoe 30l lies in the plane of shoes 299 and 300, while shoe 30!is carried by a forward extension 305 and lies in the plane of shoes 302and 303 of bracket 293. Shoe 304 of bracket 293 also is disposed in theplane of shoes 302 and 303, while shoe 304 is carried on a rearwardextension 306 and lies in the plane of shoes 299 and 300. The shoes 3Mand 30 l of bracket 292 are disposed diametrically opposite shoes 304and 304' of bracket 293. Bracket 294 has formed thereon a singlesegmental contact shoe 301 of the same length as the shoes on the otherbrackets and a shoe 308 forming practically a semicircle. Disposed inthe plane of each of the brackets at diametrically opposite points andat the height of the axis of the shaft 295 are two spring contacts D1,D2, D3, D4, D5 and De supported on an insulated base 309. Also disposedin the plane of the bracket 294 and below the bracket is a contact Dr.

The switch has three positions, namely, an intermediate neutral or feedposition which is the position in which the switch and the brackets areshown in the drawings; a rapid approach position which is assumed whenthe switch is rocked through 30 in a counter-clockwise direction, asviewed in Figs. 16 to 18; and a rapid return position which is assumedwhen the switch is rocked through 30 from intermediate position in aclockwise direction. The switch is yieidably retained inits variouspositions by means of a star wheel 3 (see Fig. 16) fast on the shaft295. Formed on the star wheel are two converging camsurfaces 3i2 and312, and at the point of convergence of the cam surfaces is a notch 3|3. Disposed to ride on the cam surfaces or drop into the notch 3l3 is aroller 3! carried on the end of a link 3|5 pivoted at its other end on apin 3i6 projecting from the rear wall of the drum switch housing M6. Theroller 3i 4 is urged into confact with the star wheel by a tensionspring 3|! at one end hooked over pin 3|8 on the lever 3i5 and at theother end anchored in an adjusting screw 3I9. When the roller 3l4engages the notch M3 the switch is yieldably held in intermediateneutral or feed position. When the switch is rocked counter-clockwise,as viewed in Fig. 16, wheel 3|4 rides on the cam surface M2 and assuresmovement of the switch to the limit permitted by engagement of anarcuate slot 323, formed in the star wheel. with a pin 32! fixed in therear wall of the switch and projecting into the slot. Likewise when theswitch is rotated in a clockwise direction the roller 3l4 rides on thecam surface 3I2 and assures movement of the switch in the oppositedirection to the extent permitted by the slot 320.

The switch may be rocked manually by the operator of the lathe orautomatically bv means driven in timed relation to the movement of thefront carriage 39. Manual rocking of the switch is employed primarilvonly to rock the switch to rapid approach position for initiating acycle of operation of the lathe and for rock n the switch to rapidreturn position to withdraw the tool and stop the lathe should theoperator find it desirable in order to prevent injury to the machine orthe work. Such rocking is effected by the lever 50 pivoted on a verticalaxis in front of the headstock where it is readily accessible to theoperator. Extending rearwardly from the lever 50 is an arm 325 connectedto one end of a link 326 terminating at its other end in a slot 321 inwhich is received a pin 328 on the star wheel 3| I. The lever 50 ismovable to an extent necessary to rock the switch to either rapidapproach or rapid return position, yet the pin and slot connection withthe star wheel 3 permits rocking of the switch by the automatic meanswithout imparting a corresponding movement to the lever 50.

Herein the means for rocking the switch automatically in timed relationto the movement of the front carriage 39 takes the form of a disk 33!!fixed on the forward end of a shaft 33| extending parallel with theshaft 295 of the switch. The rear end of the shaft 33I has keyed theretoa worm wheel 332 meshing with a worm 333 keyed to the shaft 202constituting a part of the drive to the front carriage (see Fig. 9).Adjustably mounted on the periphery of the disk 330, which is graduatedto facilitate the spacing, are

- a dog 334, a dog 335 and a dog 336. Disposed to be acted upon by thedogs in the rotation of the disk 330 is a pin 33'! projecting from anarm 333 fixed to the end of the shaft 295 projecting through the frontwall 339 of the drum switch housing. The dog 334 has a cam surface 334which engages the pin 33! to rock the switch from rapid approach tointermediate position. Dog 335 has a cam surface 335' which engages thepin 33! to rock the switch from intermediate to rapid return positionand dog 336 has cam surface 336' which engages the pinto rock the switchfrom rapid return to intermediate position. As will become apparent witha description of the electrical circuit of the lathe, the drum switch isso connected that when shifted from rapid approach to intermediateposition a feed movement is imparted to the front carriage while whenthe switch is rocked to intermediate position from rapid return thefront carriage is brought to rest. Connected between the dog 334 and thedog 335 is an arcuate bar 340 which overlies the pin 33! and preventsrocking of the thrust of the tool into the work.

With the dog 338 formed as shown in Fig. 14,

' that is to rock the switch from rapid return to intermediate orneutral position, the lathe is stopped at the end of each cycle ofoperation and is manually restarted through the lever 33. Should it bedesirable to have continuous operation of the machine with the cyclesrepeated, this is readily accomplished by substituting for the dog 336 amodified dog 34! shown in Fig. 15. The dog 3 has a cam surface 34l whichengages pin 331 and rocks the switch from rapid return through neutralto rapid approach position. Thus it is seen that with the control hereshown the lathe is readily converted from a semi-automatic to a fullautomatic machine.

Furthermore, just as the dog 3 might be substituted for the dog 336 toeffect such conversion of the machine, new dogs might also besubstituted for dogs 334 or 335 or additional dogs added to obtain acycle of operation different from the one here described. All dogs arereadily adjusted circumferentially of the disk 330 accurately to controlthe time of reversal or change of speed. The switch and the disk areattached as a unit to the casing Hi4 and are enclosed in a. housing 342having a removable cover 343.

The push button station 48 conditions the electrical circuit of thelathe and includes 'a manual switch generally designated M (see Fig. 20)having stationary terminals Mr and Mi, M2 and M'2, Ma and M's andmovable blade contacts M"1, M: and M": adapted to bridge pairs of thestationary terminals. The switch M is positioned in closed or runposition by depressing a button 345 on the push button station 48 and inopen or safe stop position by depressing a button 346. Terminals M1, M2and M3 of the switch M are connected to line wires L1, L2 and L2respectively. Terminal-M'1 is connected by a lead 341 to contact D1 ofthe drum switch and terminal M2 is connected by lead 348 to contact D4and contact Dr of the drum switch. Terminal M's is'directly connected bylead 349 to terminal T2 of the traverse motor 43. Of the remainingterminals of the traverse motor, T1 is connected by lead 350 to contactD3 of the drum switch and T2 is connected by lead 35H of con tact D2.Solenoid I43 for releasing the rapid traverse brake is connected inparallel across terminals T2 and T3 of the traverse motor. It will beapparent from the foregoing that brackets 292 and 293 of the drum switchand the contact shoes thereon exclusively govern the current to therapid traverse motor. With the drum switch rocked to rapid approachposition, contacts D1 and D: are bridged by shoes 301 and 30! andextension 305 to connect T1 to L1 and contacts .D2 and D4 are bridged byshoes 304 and 304' and bracket 293 through shoes 303 and 302 bridgescontactsDa and D4 to connect T1 and L2 and thus cause traverse motor 53to rotate in reverse direction.

Energizing current for the spindle motor does not flow through the drumswitch but the spindle motor nevertheless is controlled by the drumswitch. This isthe function of the bracket 294 and the shoes thereonwhich govern control current for a solenoid actuated switch generallydesignated So. This switch has pairs of stationary terminals S01 andSo1, S02 and So'2, S03 and 80's, and S04 and SO'4 and movable contactblades S"1,'S02, SO"3 and So"4. Terminals S01, S02 and So: are connectedrespectively to line wires L1, L2 and L3. Terminal So1 is connected bylead 352 to terminal S1 of the spindle motor 32; terminal S02 isconnected by lead 353 to terminal S2 and terminal 80's is con nected bylead 354 to terminal S2 of the spindle motor. Connected in parallel withthe terminals S2 and S3 of the spindle motor by leads 355 and 356 is thesolenoid 69 for releasing the spindle brake.

Switch So is biased to open position and is held closed by theenergization of a solenoid 358. Current may be supplied to energize thesolenoid either through the drum switch 290 or through a push buttonswitch 359, incorporated in the station 98, having stationary terminals360 and 3M and a movable bridging contact 362 biased to open positionand closed by depression of a button 363 on the push button station 48.-To that end one terminal of solenoid 358 is connected by a lead 365 tothe terminal M'2. The other terminal of solenoid 358 is connected by alead 366 to the terminal So'4 thence by lead 361 to contact 360 of thepush button switch 359 and from there by lead 368 to contact D of thedrum switch. Thus upon rocking of the drum switch to rapid approachposition after closure of the manual switchM a circuit is establishedfrom L: through the solenoid 358, leads 366, 361 and 368 to contact D5of the drum switch which is connected by bracket 294 through shoes 301and 308 a lead 369 anda lead 319 connected to contact D5 of the drumswitch which through shoe 308 is connected to contact D1. Connectedbetween leads 369 and 310 is a switch 31I actuated by a button 312 onthe push button station 48 and having a closed or. run position and anopen position for jogging the spindle, as will be described presently.

In order that the spindle may be driven without also starting the rapidtraverse motor, a lead 313 is connected between terminal M'2 of themanual switch M and contact 3.6I of the push button switch 359. Thuseven with drum switch 290 in neutral position the spindle motor may bestarted by depressing button 363. This completes a circuit from L2through manual switch M, lead 313, push button switch 359, leads 361 and366, solenoid 358 and lead 365 through manual switch M to L3 whereby thesolenoid 358 is energized and the switch S0 closed. If switch 31I is inclosed or run position, closure of the switch So again completes theholding circuit hrough contact blade So"4 and contacts D5 and D7 of thedrum switch as previously described. However, if switch SM is in open orjogging position, the holding circuit will not be established and thespindle motor will run only so long as the button 363 is held depressed.In this manner thespindle may be jogged and the carriage of the latheinched forward.

Terminals C1, C2 and C3 of the coolant motor 286 are connectedrespectively to terminals So'1. So'2 and 80's of the spindle switch byleads 314. 315 and 316. 316 is a switch 311, controlled by a button 318on the stat on 48 and having an open and a closed position. Interposedin each of the leads 341 and 349 is a current limiting device 380 andinterposed in each of the leads 352 and 354 is a current limiting device38l each having a switch 382 connected in series with the solenoid 358.

Operation The operation of the lathe is briefly as fol lows: Switch 311is first closed and switch 3H also positioned in closed or run position.To start the machine, the operator then depresses run button 345 whichcloses manual switch M and then through lever 50 rocks drum switch 290to rap d approach position. Th s completes a circuit through contacts D1and D3. and D2 and D4 of the'drum switch to rapid traverse motor 43 andthe solenoid I43 of the rapid traverse brake. Upon=energization of thesolenoid I43, core I5l thereof is pulled downwardly (see Fig. 12) andthrough links I49 and rod I41 releases brake shoes'l40 and MI, andthrough pin I68 disengages pawl I63 from notches I62 of the annular ring"50. This frees the member I32 permitting the same to be. rotated in aforward direction by the rapid traverse motor 43. Simultaneously anenergizing circuit for the solenoid 358 of the spindle switch iscompleted from L2 through lead 348, contact D71 bracket 294. contact D5.leads 368. 361'and 366, solenoid 358 and lead 365 to L2. This closes thespindle switch S0 to complete a circuit to the spindle motor 32 and thesolenoid 69 whereby the spindle brake is released and the spindle drivenby the motor Interposed in the leads 315 and 32. With both the spindlemotor 32 and the rapid traverse motor 43 rotating, the front carriage 39is rapid traversed toward the work bycarriage to rotate therewith at aspeed ,nd in a direction corresponding to the speed and direction of thecarriage movement is disk 330. Just prior to engagement of the tool,carried by the front carriage, with the work, dog 334 mounted on disk330 engages pin 331 and rocks drum switch 290 to intermediate positionwhich herein constitutes a feed position. By such rocking of the drumswitch the circuit to the rapid traverse motor 43 and the solenoid I43is broken permitting spring I49 to apply brake shoes I40 and I and bringrapid traverse motor 43, and particularly sun gear 91, to rest. PawlI63, however, does not engage a notch I62 even though released by pinI68 until the member I32 is completely at rest. This is prevented bylatch I10 which is held out of engagement with the notch I13 in pin I12until centrifugal weights I82 (see Fig. 11) are swung radially inwardlywhich occurs when the member I32 is brought to a com-' plete stop. Suchrocking of the drum switch to feed position, however, does not arrestspindle motor 32 because closure of the switch S0 had established aholding circuit through the contact blade S0"4, lead 369, switch 31I,lead 310, contact Dc and shoe 308 to contact D7. As a result thecarriage is driven at a feed speed by the spindle motor 32 through theplanetary gearing "A and the power unit B. During feed movement of thecarriage, the drum switch is prevented frombeing shifted to rapidapproach position either intentionally or unintentionally by the arcuatebar 340 which overlies the pin 331 and permits the switch to be rockedonly to rapid return position.

After the tool mounted on the carriage 39 has completed its cut, dog 335onthe control disk 330 engages pin 331 and rocks drum switch 290 fromits feed position to rapid return position. This breaks the holdingcircuit for the solenoid 358 through the contact D6 and shoe 308 to stopthe spindle motor 32 as well as the coolant motor 286. At the same timebracket 292 of the drum switch through contact shoes 300 and 299connects contacts D1 and D2 to connect terminal T2 of the rapid traversemotor to line Li and bracket 293 through shoes 303 and 302 connectscontacts Da and D4 to connect terminal T1 of the traverse motorto linewire L2 thereby causing the traverse motor to rotate in reversedirection. The solenoid I43 of the rapid traverse brake is of courseagain energized to release the brake and withdraw pawl I63 and the frontcarriage 39 is then returned to initial position at a traverse of theswitch the circuit to the rapid traverse ,the manual switch to L2.

motor and the solenoid I43 is broken to bring the motor and the sun gear91 to rest. The spindle motor is already at rest during the returnmovement of the carriage and is not reenergized by the engagement ofshoe 308 with contact Ds forming a part of the holding circuit for thesolenoid 358. A cycle of operation has thus been completed and a newcycle is initiated under the control of the operator as previouslydescribed by rocking the drum switch to rapid approach position throughthe lever 50.

Should it be desirable to repeat the cycle automatically, this may bedone by substituting for the dog 336 the dog 34I, shown in Fig. 15. Thisdog is shaped so that upon engagement thereof with the pin 331 the drumswitch is rocked from rapid return through neutral to rapid approachposition, thereby initiating the cycle above described. With the cycleautomatically repeated the lathe is started by depressing run button 345on the push button station and is stopped by depressing safe stop button346.

The spindle motor may be driven independently of the rapid traversemotor by depressing button 363 on the push button station. Thiscompletes a circuit from L2 through the manual switch M, lead 313.switch 359, leads 361 and 366 to solenoid 358 and through lead 365 andthe manual switch M to line wire L3. If the switch 31I is in run orclosed position, a holding circuit for the solenoid 35B is establishedthrough contact blade So"4, leads 369 and 310, contact Du, shoe 308 andcontact D1 of the drum switch and lead 349 through While running in thismanner the spindle 3| may be employed to drive the carriage at feedspeed or it may be disconnected from the carriage by shifting clutch II3through lever I26. If on the other hand switch 31I is in open or joggingposition, the holding circuit for the solenoid 358 will not beestablished and the spindle motor 32 will then run only so long as thebutton 363 is held depressed. In this manner by manipulation of thebutton the spindle may be inched forward under the immediate control ofthe operator.

We claim as our invention:

1. A lathe comprising, in combination. a bed, a headstock, a spindlerotatably journaled in the headstock, .an electric motor for driving thespindle, a solenoid brake for the spindle released when the motor isenergized and applied when the motor is deenergized, a carriagereciprocable longitudinally of the bed at feed and traverse speeds, aplanetary gearing having a driven sun gear connected to the carriage toimpart thereto feed or traverse movement in a forward or returndirection depending upon the speed and direction of rotation of said sungear, a driving sun gear, planetgears meshing with said sun gears, and aplanet gear carrier connected to be driven by said spindle motor, areversible electric motor for rotating the driving sun gear at a highspeed,

a solenoid brake for holding said driving sun gear against rotation,applied when said reversible motor is deenergized and released when themotor is energized, a drum switch governing the control current for saidspindle motor and brake and directly controlling the current for saidreversible motor and brake having a rapid approach position when rockedto the extreme in one direction in which both motors are energized todrive the carriage at a traverse speed in a forward direction, a rapidreturn position when rocked to the extreme in the other direction inwhich the spindle motor is deenergized and the reversible motor isenergized to rotate-in reverse direction to drive the carriage attraverse speed in a return direction, and an intermediate neutral orfeed position which if reached from rapid approach position deenergizesthe reversible motor but maintains the spindle motor energized to drivethecarriage at feed speed in a forward direction and if reached fromrapid return position deenergizes the reversible motor and maintains thespindle motor deenergized to bring the carriage to rest, a disk drivenby said driven sun gear to be rotated at a speed and in a directioncorresponding to the speed and direction of movement of said carriage,manual means for rocking said switch from neutral to rapid approachposition to energize both motors and thereby impart a rapid approachmovement to said carriage, a first dog carried by said disk for rockingsaid switch from rapid approach to feed, a second dog for rocking saidswitch from feed to rapid return, and a third dog for rocking saidswitch from rapid return to neutral.

2. A lathe comprising, in combination, a bed, a headstock, a spindlerotatably journaled in the headstock, an electric motor for driving thespindle, a carriage reciprocable longitudinally of the bed at feed andtraverse speeds, a differential gearing having a driven elementconnected to the carriage to impart thereto feed or traverse saidreversible motor and brake having a-rapid approach position when rockedto the extreme in one direction in which both motors are energized todrive the carriage at traverse speed in a forward direction, a rapidreturn position when rocked to the extreme in the other direction inwhich the reversible motor is energized to rotate in reverse directionto drive the carriage at traverse speed in a return direction, and anintermediate vneutral or feed position which if reached from rapidapproach position deenergizes the reversible motor but maintains thespindle motor energized to drive the carriage at feed speed in a forwarddirection and if reached from rapid return position deenergizes bothmotors to bring the carriage to rest, a disk driven by said drivenelement to be rotated at a speed and in a direction corresponding to thespeed and direction of movement of said carriage, manual means forrocking said switch from neutral to rapid approach position to energizeboth motors and thereby impart a rapid approach movement to saidcarriage, a first dog carried by said disk for rocking said switch fromrapid approach to feed, a second dog for rocking said switch from feedto rapid return, and a thirddog for rocking said switch from rapidreturn to neutral.

3. In a machine tool, a carriage reciprocable at feed and traversespeeds, a differential gearing having a driven element connected to thecarriage to impartv feed or traverse movement in a forward or returndirection depending upon the speed and direction of rotation of saiddriven element, a first driving element and a second driving element, afirst electric motor for driving said first driving element, a secondreversible electric motor for driving said second driving element, asolenoid brake for holding said second driving element against rotation,said brake being applied when said reversible motor is deenergized andreleased when the motor is energized, a drum switch governing thecontrol current for said first motor and directly controlling thecurrent for said reversible motor and brake having a rapid approachposition when rocked to the extreme in one direction in which bothmotors are energized to drive the carriage at traverse speed in aforward direction, a rapid return position when rocked to the extreme inthe other direction in which the reversible motor is energized to rotatein reverse direction to drive the carriage at traverse speed in a returndirection, and an intermediate neutral or feed position which if reachedfrom rapid approach position deenergizes the reversible motor butmaintains the first motor energized to drive the carrage at feed speedin a forward direction and if reached from rapid return positiondeenergizes both motors to bring the carriage to rest, a disk driven bysaid driven element to be rotated at a speed and in a directioncorresponding to the speed and direction of movement of said carriage,manual means for rocking said switch from neutral to rapid approachposition to energize both motors and thereby impart a rapid approachmovement to said carriage, a first dog carried by said disk for rockingsaid switch from rapid approach to feed, a second dog for rocking saidswitch from feed to rapid return, and a third dog for rocking saidswitch from rapid return to neutral.

4. In a machine tool, a carriage reciprocable at feed and traversespeeds, a first electric motor, a second reversible electric motor, agearing constantly in mesh connected between said carriage and saidmotors operable when said first motor is energized and said reversiblemotor is stationary to drive said carriage at a feed speed, and operablewhen said reversible motor is energized to drive said carriage at atraverse speed in a direction determined by the direction of rotation ofsaid reversible motor, a drum switch governing the control current forsaid first motor and directly controlling the current for saidreversible motor having a rapid approach position when rocked to theextreme in one direction in which both motors are energized to drive,thecarriage at traverse speed in a forward direction, a rapid returnposition when rocked to the extreme in the other direction in which thefirst motor 'is deenergized and the reversible motor is enerfrom rapidreturn position deenergizes the reand in a direction corresponding tothe speed and direction of movement of said carriage, manual means forrocking said switch from neutral to rapid approach position to energizeboth motors and thereby impart a rapid approach movement to saidcarriage, a first dog carried by said disk for rocking said switch fromrapid approach to feed, a second dog for rocking said switch from

